Searcher is a Searchable and Searchable defines the doc() method with
FieldSelector, but I suppose we could add an abstract declaration of
it to Searcher, since it has to be implemented on all derived
classes anyway due to it being on the Searchable interface.
So, you can either cast to a known Searcher or I suppose you can
figure out a way to get the IndexReader. What kind of Searcher are
you using?
-Grant
On Sep 13, 2007, at 4:50 AM, Mohammad Norouzi wrote:
Thanks
as I saw the documents, we can only use this great field selector in
IndexReader.document() method the problem is I have a Searcher in
my result
set structure and when the client calls getString("a_field_name")
at that
time I invoke the searcher.doc(current_doc_id).get("a_field_name),
I already collected the result IDs. so in my case, I can't use
FieldSelector.
Do I have to revise the way of retrieving documents in my code?
On 9/12/07, Erick Erickson <[EMAIL PROTECTED]> wrote:
Well, it depends on what "improve the search process" means
in your context <G>..
But I had a case similar to yours that I wrote up in the Wiki where
my search times improved about 10X by using lazy loading. You
might want to read that entry here...
http://wiki.apache.org/lucene-java/FieldSelectorPerformance
Note the peculiar characteristics of my data set, I really suspect
that a 10x improvement in retrieval speed is atypical...
As for when lazily-loaded fields actually get loaded, I didn't really
have to explore it very fully, but a short experiment should do it
for you.....
Best
Erick
On 9/12/07, Mohammad Norouzi <[EMAIL PROTECTED]> wrote:
Hi Grant,
Really thanks for your nice document about advanced Lucene. it
was very
useful for me.
as I understand, we can set some large fields to be lazily
loading, now
my
question is when it will be loaded? it make sense when we call
doc.get("field_name")
it will load from the index, Am I right?
in my application, I've provided a result set structure to navigate
between
results and documents and provide a get(String fieldname) method
just
like
java.sql.ResultSet.getString() method, and also this result set
implements
HitCollector in order to collect my own ID rather than Lucene's
document
id,
so I think I can set my field ID to be loaded always and the other
fields
to
be lazily loading, Does this improve the search process?
again, thank you very much indeed.
On 9/12/07, Grant Ingersoll <[EMAIL PROTECTED]> wrote:
Hi Mohammad,
The typical use cases are:
1. You have several small fields used in a results display and
one or
two large fields (i.e. the original document) and you don't want to
pay the cost of loading the large fields for results display
because
most of them won't be chosen. When a result is chosen, the lazily
loaded field will be retrieved.
2. You only want to load certain fields, or the first field, or you
just want to know the size of a field.
Basically, it gives you control over how fields are loaded from
disk
in Lucene.
See my ApacheCon Europe presentation http://cnlp.org/presentations/
slides/AdvancedLuceneEU.pdf for a few slides (towards the end) on
FieldSelector.
On Sep 12, 2007, at 5:13 AM, Mohammad Norouzi wrote:
Hi all,
Can anyone explain what is the FieldSelector and the usage or
benefits of
this structure? I read the javadocs but I can't get for what goal
it is
provided in Lucene.
Thanks in advance
--
Regards,
Mohammad
--------------------------
see my blog: http://brainable.blogspot.com/
another in Persian: http://fekre-motefavet.blogspot.com/
--------------------------
Grant Ingersoll
http://lucene.grantingersoll.com
Lucene Helpful Hints:
http://wiki.apache.org/lucene-java/BasicsOfPerformance
http://wiki.apache.org/lucene-java/LuceneFAQ
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Regards,
Mohammad
--------------------------
see my blog: http://brainable.blogspot.com/
another in Persian: http://fekre-motefavet.blogspot.com/
--
Regards,
Mohammad
--------------------------
see my blog: http://brainable.blogspot.com/
another in Persian: http://fekre-motefavet.blogspot.com/
------------------------------------------------------
Grant Ingersoll
http://www.grantingersoll.com/
http://lucene.grantingersoll.com
http://www.paperoftheweek.com/
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